After towing the Earth back into place, everyone went to rest and recover from the day's events except for the Doctor. He stood by himself at the console, his hearts heavy as he thought over what he had to do with Rose and his clone. He hated to do it but he couldn't see any other option, his clone was too dangerous to be alone and he wasn't about to tolerate having him in the same universe. Besides, he saw a golden opportunity to give Rose a part of himself that she could truly love and who could love and grow old with her in return.

He finished inputting the coordinates for Ealing when Donna entered the room. The Doctor glanced at her and his hearts hurt anew, knowing that he also must make a huge sacrifice with her.

"Everyone's resting but I wanted to see if you were alright," Donna said, walking over to him.

"I'm alright," the Doctor said, trying to put on a cheerful demeanor.

Donna snorted.

"Don't give me that, you're far from alright," she said. "That whole sunny personality 24/7 might work with other people but you're not foolin' me."

"I'm just upset, alright?" the Doctor said, dropping the act.

"About what?" Donna said gently.

The Doctor glanced at the back door and making sure no one was there, he told Donna what his plans were for Rose and his clone.

"Are you sure that's what you want to do?" Donna asked him when he finished speaking.

"Yes. I have to do it. She deserves the best," the Doctor said.

"So do you."

The Doctor didn't reply to that and Donna sighed, knowing that once again her friend was sacrificing his own happiness for the greater good. With her Time Lord mind, she now understood his motives better but she still didn't agree that he needed to give up every shred of happiness to someone else.

The Doctor stood up to check on their progress at the console when suddenly Rose dashed into the room and zoomed towards him.

"THERE YOU ARE!" she squealed as she barreled into him. "DON'T EVER LEAVE ME!"

The Doctor gasped when she flung herself around him and held him tight. His hearts beat rapidly as he thought that perhaps Rose had been standing at the back door listening to everything they said and he was about to explain his reasons why she needed to go back to Pete's World when Rose chuckled and ruffled his hair affectionately.

"So…still up for going to that planet that does the Siamese twin surgeries?" she said to him.

Then it dawned on him what was going on and his heart ached as that long ago memory of the practical joke came into focus in his mind's eye. He realized with a sinking heart that Rose didn't know what his plans were after all. He suspected that Jack had cornered her again and asked her to play the joke on him again for old time's sake. Rose, meanwhile, was looking back at Donna.

"What?" Donna said while the Doctor couldn't help but grin at her confusion. "You wanna be attached to him?"

"Forever," Rose said with a shrug. "I'm sure there's a hospital somewhere that does Siamese twin surgeries but he won't say where."

"What?" Donna said, laughing, when the Doctor looked over his shoulder, spun his finger around his ear and pointed to Rose.

"Me and him, we're a team, you know," Rose said, pointing to him. "And I get all blue if I'm more than five feet away from him at any time."

"I thought it was two feet and you got icky," the Doctor said.

"Yes, that's right. Two feet and icky, that's me," Rose said.

The Doctor tried to be lighthearted and join in but the thought of Rose innocently playing this joke and saying all these things without knowing what was going to happen soon tore at his hearts and he turned his head away from her in guilt and shame. Rose turned to him, a big grin on her face but it dropped off his face when she noticed he seemed to be in distress.

"Doctor, I'm just having you on, like before," Rose said, putting her hand on his back. "I know you got a bit irritated the last time but Jack thought that since we were here that I should do this for old time's sake. I don't have the handcuffs though. Jack probably used them…on what, I dread to think."

The Doctor laughed a sad laugh at that but wouldn't meet Rose's eyes. His breath caught in his throat when Rose leaned her head against his back.

"I'm so glad I found you again," she murmured.

The Doctor swallowed hard.

"Me too," he said, amazed that he could keep his voice so steady.

He tried not to stiffen when Rose put her arms around him from behind.

"My security blanket," she murmured as she closed her eyes.

Donna sensed that the Doctor was about to lose it and she quickly stood up and walked over to Rose.

"Hey, wanna get a cuppa and have a little chat?" she said to Rose.

"Yeah, cuppa sounds good. But you stay here because I might need you again in five minutes," Rose said, playfully poking the Doctor's back.

The Doctor nodded, too choked up to do anything else. Donna quickly got Rose away from him and the Doctor glanced back over his shoulder and let out a shuddering sigh when they finally left the room. When he was alone, he let a tear fall from his eye and allowed himself a few moments of grief before he forced himself to pull himself together and go get Sarah Jane for the first stop home.